1. Field of the Invention
The present invention relates to a ceramic chip-type electronic component such as a multilayer ceramic capacitor or a chip resistor, for example. The invention further relates to a method of making such an electronic component.
2. Description of the Related Art
Conventionally, a multilayer ceramic capacitor generally includes a chip body and at least one pair of external electrodes. The chip body is formed by sintering a plurality of ceramic green sheets laminated one upon another. A single pair of external electrodes is utilized as parts for a single capacitor element. The external electrodes are formed by sputtering of metal such as copper or by the application of metal paste such as copper paste, for example.
The multilayer ceramic capacitor having the above-described structure has a drawback that the chip body easily cracks or chips. For instance, when the multilayer ceramic capacitor is soldered on e.g. a printed circuit board, such cracking or chipping may occur due to the shock from the outside or the thermal expansion difference between the multilayer ceramic capacitor and the printed circuit board.
To solve such a problem, JP-A-2003-7567 (hereinafter referred to as “document 1”) discloses a chip-type electronic component in which a conductive elastic resin film is formed on a surface of the chip body to prevent such cracking or chipping. The chip-type electronic component is so mounted on a printed circuit board that the surface with the conductive elastic resin film faces the printed circuit board. Therefore, the elasticity of the conductive elastic resin film absorbs the shock from the outside to the chip body or the thermal expansion difference.
Similarly, to prevent the cracking or chipping, JP-A 2004-296936 (hereinafter referred to as “document 2”) proposes to form a conductive elastic resin film on an external electrode. In the technique disclosed in this document, the width of the conductive elastic resin film is equal to that of the external electrode.
According to the above-described document 1, the elasticity of the conductive elastic resin film absorbs the shock or the thermal expansion difference. In this structure, however, the external electrode of the chip-type electronic component is bonded to the printed circuit board via a solder fillet. Therefore, in spite of the provision of the conductive elastic resin film, the influence of the shock or the thermal expansion difference is not sufficiently lessened, and hence, the cracking or chipping of the chip body may not be effectively prevented.
According to the above-described document 2, a conductive elastic resin film having the same width as that of an external electrode is provided on the external electrode. In this structure, the side surfaces of the external electrode are exposed without being covered by the conductive elastic resin film. Therefore, when the chip-type electronic component is mounted on a printed circuit board, a solder fillet is formed on the exposed side surfaces of the external electrode. Therefore, similarly to the structure of the document 1, the external electrode is bonded to the printed circuit board via the solder fillet, so that the cracking or chipping of the chip body may not be effectively prevented.
Further, in the structure of the document 2, the conductive elastic resin film contacts only one surface of the external electrode and does not directly support the chip body. Therefore, there is a large possibility that the conductive elastic resin film separates due to the shock from the outside to the chip body or the thermal expansion difference.